Exhibit 5

        Simpson Thacher & Bartlett LLP
425 Lexington Avenue
    New York, New York 10017-3954

August 5, 2003

Amphenol Corporation
358 Hall Avenue
Wallingford, Connecticut 06492

Ladies and Gentlemen:

        We have acted as counsel to Amphenol Corporation, a Delaware corporation (the "Company"), in connection with the Registration Statement on Form S-3 (the "Registration Statement") filed by the Company with the Securities and Exchange Commission (the "Commission") under the Securities Act of 1933, as amended (the "Act"), relating to 10,000,000 shares of Class A Common Stock, par value $0.001 per share (together with any additional shares of such stock that may be registered by the Company pursuant to Rule 462(b) (as prescribed by the Commission pursuant to the Act) in connection with the offering described in the Registration Statement, the "Shares"). The Shares may be sold or delivered from time to time as set forth in the Registration Statement, any amendment thereto, the prospectus contained therein (the "Prospectus") and supplements to the Prospectus (the "Prospectus Supplements") and pursuant to Rule 415 under the Act.

        We have examined the Registration Statement and a form of the share certificate, which has been filed with the Commission as an exhibit to the Registration Statement. We also have examined the originals, or duplicates or certified or conformed copies, of such records, agreements, instruments and other documents and have made such other and further investigations as we have deemed relevant and necessary in connection with the opinions expressed herein. As to questions of fact material to this opinion, we have relied upon certificates of public officials and of officers and representatives of the Company.

        In such examination, we have assumed the genuineness of all signatures, the legal capacity of natural persons, the authenticity of all documents submitted to us as originals, the conformity to original documents of all documents submitted to us as duplicates or certified or conformed copies, and the authenticity of the originals of such latter documents.

        Based upon the foregoing, and subject to the qualifications and limitations stated herein, we are of the opinion that the Shares have been duly authorized and are validly issued, fully paid and nonassessable.

        We are members of the Bar of the State of New York and we do not express any opinion herein concerning any law other than the Delaware General Corporation Law (including the statutory provisions, all applicable provisions of the Delaware Constitution and reported judicial decisions interpreting the foregoing).

        We hereby consent to the filing of this opinion letter as Exhibit 5 to the Registration Statement and to the use of our name under the caption "Legal Matters" in the Prospectus included in the Registration Statement.

Very truly yours,

/s/  SIMPSON THACHER & BARTLETT LLP

SIMPSON THACHER & BARTLETT LLP